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bompus merged 2 commits into from
Oct 10, 2026
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docs(mcp-relay): list the memory each launch command costs #127

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docs(mcp-relay): list the memory each launch command costs
bompus Oct 10, 2026
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docs(mcp-relay): say the repository's relay tests run under Node only
bompus Oct 10, 2026
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3 changes: 3 additions & 0 deletions CHANGELOG.md
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Original file line number Diff line number Diff line change
Expand Up @@ -11,6 +11,9 @@ Notable changes to Swarmail. Versions follow [semantic versioning](https://semve
which is the default. A page of 20 messages took 48 µs instead of 57 µs with 2 KB bodies and 52 µs instead of 82 µs
with 17 KB bodies.

- The `swarmail-mcp` README lists the memory each launch command costs: about 180 MiB for `npx -y swarmail-mcp`, 82 MiB
for `bunx swarmail-mcp` and 46 MiB for `bunx --bun swarmail-mcp`, which runs the same relay under Bun.

## 0.5.2 - 2026-10-09

- Require agents to record whole-session closeouts and retire their own project
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18 changes: 18 additions & 0 deletions packages/mcp-relay/README.md
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Expand Up @@ -17,3 +17,21 @@ It forwards each JSON-RPC message to `SWARMAIL_URL`
(default `http://127.0.0.1:18765/mcp/`). Node 18 or newer, no dependencies.
Hosts that support MCP over HTTP can skip the relay and use that URL directly,
which is what `scripts/configure-mcp.ts` sets up.

## Memory

Each MCP client that launches the relay keeps its own process tree running.
On one Linux machine, with the relay idle after a first request:

| Command | Memory, whole process tree |
| ------------------------- | -------------------------- |
| `npx -y swarmail-mcp` | about 180 MiB |
| `bunx swarmail-mcp` | about 82 MiB |
| `bunx --bun swarmail-mcp` | about 46 MiB |

Most of the `npx` figure is the `npm exec` process that stays running beside
the relay. `bunx` alone still runs the relay under Node, because the script's
`#!/usr/bin/env node` line wins; `--bun` runs it under Bun. The relay is plain
JavaScript with no dependencies, so it runs unchanged under Bun, but the
repository's relay tests run it under Node only. Use `--bun` only where Bun is
installed.
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